This invention concerns a method and a machine for making a spring-mattress web. The invention further relates to a mattress web made using the machine of the invention, in accordance with the method of the invention.
WO 91/05732 teaches a method and a machine for encapsulating elongated springs between two fabric webs, thereby to produce a mattress web.
One drawback of this prior art technique is that, when the shuttle by means of which a spring is introduced between the fabric webs is retracted, there is a considerable risk that the friction between the shuttle and the spring as well as between the webs and the spring will stretch the spring in its longitudinal direction, such that the spring will, when trying to revert to a non-tensioned state, contract or crease the webs. As a result, the webs have to be stretched in the transverse direction in the mattress web or in the mattress blank separated from the mattress web, which is a costly operation.